In the past, the processing for change of colored thread, etc. used to be performed with manual work of an operator.
By the way, in a processing for change of colored thread, etc., the sewing machine must be stopped, and, especially in the case of a change of colored thread, it is necessary to change the colored thread on each of the sewing machine heads provided in the number of several pieces to as many as 30 pieces in some cases on a single embroidery machine. This stopping time could last for several hours, presenting a problem of drop of operating rate and productivity of the sewing machine.
In view of the problem of the conventional embroidery machinery, this inventor previously proposed embroidery machinery capable of performing the processing for change of colored thread without intervention of an operator (see PCT/JP97/02601 and PCT/JP97/02602).
This embroidery machinery, which can automatically perform the processing for change of colored thread without intervention of an operator, could shorten the time required for such operation and, therefore, had an advantage of the possibility of improving the operating rate and productivity of the sewing machine.
However, this sewing machine had a problem of somewhat low accuracy of threading.